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Kossmat’s zonation of the Central European basement in the light of the current knowledge

Although almost a century old, the pioneering subdivision of the Central European basement by Franz Kossmat (1927) is still the most widely used zonation to describe the principal architecture of the currently exposed Pre-Mesozoic crust. By correlating lithological, paleontological, metamorphic, and deformation features, Kossmat distinguished four major zones, namely the Rheno-Hercynian, Moravo-Silesian, Saxo-Thuringian, and Moldanubian zones. Over the years, his subdivision was modified and extended to the entire Variscan orogen. With the acceptance of the plate tectonic theory half a century later, the zonation was reinterpreted to reflect a pre-Variscan paleogeography. Consequently, terranes or microplates were initially separated by oceanic lithosphere, implying that zone boundaries represent sutures.

Numerous modern data challenge such a direct correlation of Kossmat’s classical zones with pre-orogenic characteristics. The pre-orogenic detrital record reveals three major sediment provenances, namely Laurussia, West Peri-Gondwana, and East Peri-Gondwana. The resulting provenance patterns do not correlate well with the zonation. For example, the Moldanubian Zone of the Bohemian Massif has been correlated with the French Massif Central and the Central Iberian Zone where it comprises a mixture of Laurussian and Peri-Gondwanan, West and East Peri-Gondwanan, and East Peri-Gondwanan sediments, respectively. We show how the pre-orogenic constellation was blurred by polyphase Variscan tectono-metamorphic overprinting associated with high-grade metamorphism and exhumation-related nappe stacking, followed by late orogenic equilibration and multiple post-orogenic tectonic events, in particular Late Carboniferous-Permian extension. Furthermore, the integration of new observations leads to correlations across zonation boundaries, allowing us to better understand the magmatic and metamorphic evolution, and mineral deposits.

Details

Author
Uwe Kroner1, Tobias Stephan2
Institutionen
1TU Bergakademie Freiberg, Germany; 2Lakehead University Thunderbay, Canada
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/2kt9-t904